Buildings have traditionally been designed to support their own weight plus that of expected inhabitants and furnishings. Buildings and other structures for supporting weight have long been expected to be very strong under vertical compression. Concrete is a favorite material for weight-bearing structures because it is inexpensive and has exceptional compressive strength.
In the mid-1900s, architects began to take lateral forces into account more than they had previously. Wind can exert strong lateral force on tall buildings and long bridges. Smaller structures were still designed without much regard for strong lateral forces until concern for earthquake resistance began growing in the 1970s in the United States, partly due to the massive Anchorage earthquake in 1964.
Many buildings are still in use that were not built to withstand strong lateral forces. Some smaller structures, such as masonry block walls have almost no built-in resistance to lateral forces. These could be toppled or collapsed by an earthquake and kill or injure people.
There is a need for a means to reinforce old structures so that they resist strong lateral force, such as could be caused by earthquake, storm, or explosion. Some present techniques for reinforcing structures require encapsulation of the structure in steel rods or panels, sprayed-on concrete, or resin-impregnated fiber panels. Other techniques require extensive excavation next to the structure or addition of external buttresses. These present techniques have disadvantages and are not applicable to all situations.
New structures are often built of multiple prefabricated components, such as concrete beams, columns, or masonry blocks; combinations of prefabricated and poured-in-place components are also used. In the past, gravity and friction were frequently the main means of passive connection of components. For example, a structure consisting of a slab deck atop prefabricated columns will stay in position indefinitely, as long as the structure is only supporting its own weight and the weight of the people, vehicles, or other components that are on the slab.
To withstand lateral forces such as seismic or wind forces, however, a structure's components must be strongly connected together. Yet, it has been found that extremely rigid structures do not fare as well in earthquakes or wind as structures with some flexibility.
The connector of the present invention is an inexpensive and effective way to reinforce many types of structure. The present invention can be installed in a small area with minimal disruption of the functioning of an existing and occupied structure. The connector is also useful and cost-effective for reinforcing new structures.
The invention is an efficient way to reinforce masonry block walls and large structures that include slabs columns, and beams.